With land becoming more scarce than ever, buildings are sometimes constructed on stilts over the Chao Phraya. Garbage gets stuck underneath the buildings and can become a hazard. Image by Adam Janofsky. Thailand, 2012.

Longtail boats, like the one seen here, characteristically use salvaged truck engines for motors. The exhaust goes directly into the rivers. Image by Adam Janofsky. Thailand, 2012.

Any waste that can't stay on the streets often gets thrown into the waterways. Here, a dead dog floats along the Chao Phraya. Image by Adam Janofsky. Thailand, 2012.

Young men swimming in the Chao Phraya River. Image by Adam Janofsky. Thailand, 2012.

Other Southeast Asian cities—Ho Chi Minh City is shown here—have dodged traffic holdups thanks to motorcycles. However, the exhaust from millions of motorcycles is creating air pollution problems. Most drivers shown are wearing surgical masks to avoid the fumes. Image by Adam Janofsky. Vietnam, 2012.

Three tiers of roads in central Bangkok. The growing number of vehicles has created a need for more streets and public transportation, but there is often a lack of space. Image by Adam Janofsky. Thailand, 2012.

A haze of smog envelops Bangkok on a hot mid-afternoon in June. Image by Adam Janofsky. Thailand, 2012.

The Bangkok Metropolitan Administration collects 8,000 tons of trash daily, but hundreds of tons more never get processed. The streets and waterways of Bangkok double as garbage disposals, and pollution has reached a “critical level,” according to the government’s Pollution Control Department.

The issue is more than just dumping trash. Boats that ride on Bangkok’s Chao Phraya River use salvaged diesel truck engines that spew exhaust directly into waterways. Waterside buildings freely pump waste into the river. And the health effects can be grave: People swim in the trash-filled canals, and the city’s drinking water is contaminated from waste. Bangkok’s largest environmental issue has become a lack of clean water, but smog and air pollution are also serious threats to health.